This project aims to characterize psychological and psychobiological attributes that are associated with alterations in smooth pursuit eye movements. The smooth pursuit system regulates the eyes' smoothly following a moving target and can be measured by an electro-oculograph recording of an individual watching a moving pendulum. By using the high-risk strategy of screening a large group of college student normal volunteers, individuals with various alterations in smooth pursuit patterns will be identified. Individuals with two common types of alterations will be compared with those with more accurate tracking using a variety of psychological and biological tests to explore the relationship of these patterns to personality, psychophysiological and biochemical variables.